Fixes #11043: Blacklist certain pages that are used to edit and create resources, while still leaving open the possibility of bookmarking Wiki Change History pages (action=history) and diffs (action=diff). This behavior might be re-evaluated later and is therefore subject to change.

Refs #11071: Replaced string interpolation in SQL strings with proper argument passing to the Trac Database API. This should resolve cross-DB compatibility issues, including the PostgreSQL issues described in #11071.

Fixes #7540: Added a datepicker for the start and end date. The datepicker will only be available in Trac 1.0 and later, in which jQuery UI is distributed with Trac.

The feature could be made available in earlier versions of Trac by including jQuery UI directly (see for example how this is done in backlogplugin/trunk/backlog/web_ui.py?rev=12796​), but I won't bother with this unless someone asks for it.

Finding any non-standard/default permission policy, fine-grained permission
checking will be enforced, intentionally removing the opt-out for safety.
Thanks to Odd Simon Simonsen for bringing-up the idea in the first place.